1. Field of the Invention
The present invention relates to a ball nut, and more particularly to a ball nut having a guiding or positioning device engaged into a nut member and having return channels for aligning with the threads of the nut member and for forming endless passages to receive rollers or balls.
2. Description of the Prior Art
Typical screw shafts comprise a screw member threaded into a nut member, or relatively, a nut member threaded onto a screw member, and a number of rollers or balls engaged in the threads of the nut member and the screw member for facilitating the rotational or sliding movement between the nut member and the screw member.
For allowing the rollers or balls to be cyclically and smoothly engaged in or moved along the threads of the nut member and the screw member, one or more tubular members, return tube arrangements, deflectors or the like are engaged into or onto the nut member and each include an inner channel for aligning with the threads of the nut member and for forming endless passages to receive the rollers or balls.
For example, U.S. Pat. No. 3,971,264 to Detraz et al., U.S. Pat. No. 5,014,568 to Schlenker, and U.S. Pat. No. 5,063,809 to Schlenker disclose three of the typical ball nuts each also comprising one or more tubular members, return tube arrangements, deflectors attached to the nut member for forming the endless guide passages and for receiving the rollers or balls.
Normally, the nut member is required to be drilled with two or more holes for aligning with the threads of the nut member and for engaging with the tubular members, the return tube arrangements, the deflectors or the like and for cyclically receiving the rollers or balls.
However, it will be difficult to drill holes in the middle portion of the nut member due to the rounded outer peripheral surface of the nut member, and it will be much more difficult to drill and align the holes with the threads of the nut member because the threads of the nut member may not be seen while drilling or machining the holes in the nut member.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional guiding members for the ball nuts.